RE: 3.3V PCI Motherboard

["O'Shea, David J" <david.j.oshea@intel.com>]

Judy,

3.3V signalling systems that I know of are all based
on 66Mhz bus solutions some of which can also run down at
33Mhz.  These are Intel i840 and Intel Profusion (TM)
chipset based systems.  

All systems based on Intel Profusion 8-way chipset have
will do what you want, but your bring $$.

Some systems based on Intel 840-chipset.  (Usually
those providing a 66Mhz bus, which can run at 33Mhz
with a 33Mhz board installed).   

http://developer.intel.com/design/chipsets/840/

The Intel i840 based systems will be much cheaper than 8-way chipset
Profusion systems.  Most of the i840 systems are still in
final development, and won't be out for a month or two.  A couple
of the fastest movers are shown below.

Tyan S2257 Thunder 2400.  Their page also does not mention
if their 66Mhz slots can downshift to 33Mhz.
http://www.tyan.com/products/html/s2257.html

Super Micro has some i840 boards w/ 66Mhz 3.3v signalling,
but they don't say if these slots will downshift to 33Mhz.
You would have to ask them:
http://www.supermicro.com/PRODUCT/MotherBoards/840/PIIIDME.htm
http://www.supermicro.com/PRODUCT/MotherBoards/840/PIIIDM3.htm
http://www.supermicro.com/PRODUCT/MotherBoards/840/PIIIDM6.htm

All of the systems based on the Intel Profusion (TM) chipset
have some slots with 3.3V signalling.  You can buy these now.
The ones below have some 3.3V signalling slots at 64 bit width,
but 32 bit devices work fine in a 64 bit slot.   The 3.3V slots
are actually targeted at 66Mhz adapter boards, but the systems
based on the Intel Profusion (TM) chipset also handle 33Mhz device
plugged into those slots.  In that case the 3.3V slots
run at 33Mhz clock and 3.3V signalling, which is what
you are after.

This includes the 
Dell Poweredge 8450  http://www.dell.com
http://www.dell.com/us/en/bsd/products/spec_rkopt_8450_servers.htm

Compaq Proliant 8500 http://compaq.com

The 8-way HP vectra is also a Profusion. http:www.hp.com
As are:
IBM 8-way		
Hitachi 8-way
Unisys 8-way
and most of the 8-ways on the market.

Unfortunately, all of the Profusion systems are fairly expensive
as a PCI test bed.  (High end 8-way Intel box, much more expensive
than an average PC, much less expensive than comparible RISC
machines....  I had to put in the ad, just couldn't resist).

In terms of your search for a system, the easiest thing
to do would be to look for systems with 66Mhz bus support.
The 66Mhz busses are required to use 3.3V signalling.   The
66Mhz bus slots are all keyed for 3.3V signalling.  Most,
but not all of the 66Mhz systems will also run at 33Mhz
on those 66Mhz capable busses if a 33Mhz board is plugged in.
Note, that in this last case, you get 33Mhz at 3.3v signalling
in the slot keying and the signalling environment.  But you 
need to ask the motherboard manufacturer.  It is board and BIOS
design decision.

None of the manufacturers tend to brag about their 3.3V or 5V
signalling.  But they do brag when they have 66Mhz slots.  All
the 66Mhz slots are 3.3V signalling by requirement.  Many, but
not all of the 3.3V 66Mhz slots on systems can often run at 33Mhz
with 3.3V signalling.

(I suppose some 8-way systems, in the cheapest 1-CPU configuration,
might be reasonably affordable as a test bed.   The Dell, Compaq, IBM,
HP, Unisys systems above all provide both 5V 33Mhz and 3.3V 66Mhz 
or 33Mhz operation slots.   So one system would cover a lot of ground....

-David O'Shea
Intel Corp.
david.j.oshea@intel.com




-----Original Message-----
From: Judy Fuess [mailto:JudyF@motioneng.com]
Sent: Thursday, January 20, 2000 10:36 AM
To: Mailing List Recipients
Subject: 3.3V PCI Motherboard


Hi,

I have a universal PCI board that I would like to test in a 3.3V 33MHz PCI
slot. I was wondering
if anybody know of PCs or Motherboards that are available with this.

	thanks in advance,

	Judy Fuess
	Design Engineer
	Motion Engineering Inc.
	805-681-3300